A halogen-substituted phthalide is, for example, an important compound as a raw material, an intermediate and a bulk of pharmaceuticals and pesticides. Particularly, 4,5,6,7-tetrachloro-1(3H)-isobenzofuranone (another name: 4,5,6,7-tetrachlorophthalide) is widely known as a bactericide for rice blast (see, for example, JP-B-46-15094).
Gazzetta Chimica Italiana, 87, p. 1147 (1957) describes, as a method for producing a halogen-substituted phthalide, for example, a method in which tetrachlorophthalic anhydride is reacted with lithium aluminum hydride to obtain 4,5,6,7-tetrachloro-1(3H)-isobenzofuranone.